Python interview questions with answers

Introduction

Preparing for a Python job interview? We’ve compiled a list of essential Python interview questions and answers to help you succeed.

These resources are designed to guide you through your preparation and boost your confidence for the interview.

What is Python?

Python is a programming language which is very versatile and easy to learn and understand. It has clean and intuitive syntax which helps in focusing more on important tasks like making logic and program structure.

It is very versatile and used across various domains like web development, data science and automation, AI, etc.

Why Python?

Python is a high level and interpreted programming language which is known for its simplicity and readability.

Guido Van Rossum created this language. It has become one of the most popular languages due to its versatility and ease of use.

It’s syntax is clear and straightforward which makes it excellent choice for beginner as well as experienced programmers.

What kind of application you can use Python in?

Python is a incredibly versatile language and can be used in a wide range of applications such as Web applications, Data science and Machine learning, etc.

Python is widely used for building web applications through frameworks like Django and Flask, furthermore these frameworks allow for rapid development of scalable and secure websites and web services.

List advantages of Python?

There are various key advantages of Python which makes it one of the popular languages today.

It has clean and simple syntax that mimics natural language which makes it an excellent choice for beginners. This helps programmers to fous on more important tasks like problem-solving.

What is PEP 8?

PEP 8, or Python Enhancement Proposal 8, is the official style guide for writing clean and readable Python code. 

It provides conventions and best practices for formatting Python code to ensure consistency and improve readability across different Python projects.

What are Python literals?

In Python, writing the fixed values directly into the code is Python literals. These are constant values which represent data in Python program.

We assign Python literals of various types to variables or use them directly in expressions. Let’s breakdown different types of literals in Python.

What is Python’s parameter passing system?

The Python’s parameter passing system is often a topic of confusion, but understanding how it works is important.

Python uses a mechanism known as “pass-by-object-reference” (sometimes called “pass-by-assignment”).

How to overload methods or constructors in Python?

In Python, overloading methods or constructors doesn’t exists in traditional sence like in other programming languages(C++ or Java). Which means that Python doesn’t allows you to define multiple methods or constructors with the same name but different parameters.

However, you can achieve similar functionality using default arguments, variable-length arguments, and special methods.

What is __init__?

We often refer to the special method __init__ in Python as a constructor. Moreover, we automatically call the special method __init__ when we create a new instance of a class.

We use it to initialize the object’s attributes and perform any setup operations needed for the instance.

The __init__ method allows you to define the initial state of an object which is an essential part of object-oriented programming in Python.

What is the difference between Python array and Python list?

We use both the array and the list to store data but there are difference between Python array and Python list.

What is slicing?

We can extract a part of information from a list, a sequence or a tuple with the help of Python slicing.

It will allow you to access a subset of information from a sequence without modifying the original data.

What are unit test?

We can test the correctness of a small, individual units of code. Such as functions of code with the help of Python unit test.

We can check if a functionality in a program works as expected. When we isolate it from the rest of the program.

This helps us identify the bugs in the development phase and also determine the logic is working as we expect.

What are docstring?

Python Docstrings are special strings that we use to explain the purpose of a code. It can be a method, a module, a class, a function or code.

By using docstrings, we can explain how the specific code does, how it works and how to use it.

Docstrings are a critical part of Python code, as they help developers understand the purpose and functionality of the code. Especially when working in team on large codebases.

What are control flow statements in Python?

Continue, break, and pass are control flow statements in Python, that are used to alter the flow of execution within loops or conditional statements. 

What is the self in classes in Python?

The self in Python classes is a convention which is used in instance methods of classes.

It refers to the instance of the class that is being manipulated or operated on.

In other words, self allows you to access the attributes and methods of the current object, and it is used to differentiate between instance variables (attributes) and local variables within methods.

What are different attributes in Python?

Attributes in Python of a class or variable can have different levels of visibility and accessibility.These levels are controlled using the global, protected, and private naming conventions.

These conventions define how variables or methods can be accessed from outside the class, module, or function.

However, it’s important to note that Python does not strictly enforce these access control mechanisms, but uses conventions and some syntactic rules to indicate how an attribute should be accessed.

What are built in datatypes in Python?

Python’s built-in data types refers to the types of values that Python provides. Which is to represent different kinds of data.

They are the fundamental types of values it uses to represent different kinds of data.

These data types are fundamental for performing various operations and they are essential for any Python program.

What is a scope in Python?

A scope in Python refers to the region of the code where a particular variable or name is accessible or visible.

It defines the context in which a variable or function can be referenced or modified.

Understanding scope is essential for managing the visibility and lifetime of variables, especially in larger programs where multiple variables might have the same name in different contexts.

How interpreted language works?

An interpreted language is a type of programming language in which most of the instructions are executed directly, line by line, by an interpreter at runtime, rather than being compiled into machine code beforehand (like in compiled languages).

What is list comprehension?

List comprehension is an efficient way to create a list in Python. These comprehension will allow you to create new data structures by iterating over an iterable and optionally applying an expression or condition to each elements.

It provides a more compact and readable way to create lists by specifying the elements to include in the list based on some existing iterable (such as a list, range, or any other iterable object).

How to use a Python decorator?

A Python decorator is a design pattern that allows you to add or modify functionality to functions or methods without changing their actual code. Decorators are functions that take another function as an argument and extend or alter its behavior, returning a new function with the enhanced functionality.

Decorators are commonly used in Python to:

• Add functionality to functions or methods.
• Modify or extend the behavior of a function in a reusable and readable way.
• Apply cross-cutting concerns like logging, access control, or memoization.

What are Python namespaces?

The Python namespaces are container that holds a collection of variable names (identifiers) and their corresponding objects (values).

It is essentially a mapping between names (such as variables or functions) and objects in Python.

Each namespace ensures that names are unique and avoids name conflicts. Python uses namespaces to keep track of all variables, functions, and objects in the program to prevent clashes between identifiers.

How to use lambda in Python?

A lambda in Python refers to an anonymous, small, and simple function that can have any number of arguments, but can only have a single expression.

The function is defined using the lambda keyword, and unlike regular functions defined with def, lambda functions don’t have a name (hence the term “anonymous”).

What are Python negative indexes?

In Python, negative indexes allows you to access elements of sequences (like lists, tuples, or strings) from the end of the sequence, rather than from the beginning.

This is a convenient feature because it lets you easily refer to elements at the end of a sequence without needing to know its length.

Why do we use join() function in Python?

The join() function in Python is a string method used to concatenate (join) a sequence of strings (such as a list, tuple, or other iterable) into a single string, with a specified separator between each element.

Syntax of join() function :

separator_string.join(iterable)

How to use break statement in Python?

The break statement in Python is used to terminate the execution of a loop (such as for or while) prematurely, meaning that it allows you to exit the loop before it has iterated over all elements or satisfied its condition.